Generally, a power window system includes a button for receiving a window opening or closing signal and a window motor for opening or closing a window in each door of a vehicle in response to the signal to allow a driver to easily open and close the widow.
Particularly, the power window system may include an automatic up/down button to completely open or close the window by one-time manipulation by the driver.
Recently, a case in which a finger of a child is jammed and injured in a space between the window and a door frame during a rise of the window by the automatic up button has often occurred.
In order to solve this problem, a power window system (hereinafter, referred to as a safety power window system) having a jamming prevention function of preventing an injury to a human body by lowering the window through reverse rotation of the window motor when jamming of an object during the rise of the window is sensed has been developed.
A safety power window system according to the related art calculates force acting on the window using a pulse waveform generated by a hall sensor depending on a polarity of a corresponding magnet at the time of rotation of a motor rotor, and determines that the object is jammed between the window and the door frame to lower the window when the calculated force exceeds a threshold value.
In the safety power window system according to the related art, a safety power window function is implemented using a single hall sensor. Therefore, only in the case in which the number of pulse waveforms generated by the hall sensor is two or more, that is, corresponding to the case in which the window motor rotates twice or more, an acceleration of the window motor may be calculated, and force acting on the window may be calculated through the acceleration.
In another safety power window system according to the related art, the safety power window function is implemented using two hall sensors positioned to have an interval of 90 degrees therebetween. Therefore, only in the case in which the window motor rotates 1.5 turns or more, the acceleration of the window motor may be calculated, and force acting on the window may be calculated through the acceleration.
As a result, in the safety power window systems according to the related art, force acting on the window may not be calculated in an extreme situation in which the window motor may not rotate once or more. Therefore, the safety power window systems according to the related art may not detect the jamming of the object between the window and the door frame.